(a) Field of the Invention
The present invention relates to a method and system for adjusting a gray-scale level of a liquid crystal display device.
(b) Description of the Related Art
In general, liquid crystal displays (LCDs) include two display panels, each having pixel electrodes and a common electrode formed thereon, and a liquid crystal layer having anisotropic dielectric interposed between the two display panels. The pixel electrodes are arranged in a matrix, and are connected to switching elements, such as thin film transistors (TFTs). The common electrode is formed on the entire surface of the corresponding display panel, and a common voltage is applied to the common electrode. The pixel electrode, the common electrode, and the liquid crystal layer interposed therebetween form a liquid crystal capacitor in a circuit structure. The liquid crystal capacitor and the switching element connected thereto constitute a unit pixel. A data voltage is applied sequentially to rows of the pixel electrodes.
In the liquid crystal display, a voltage is applied to the two electrodes to generate an electric field in the liquid crystal layer. The electric field intensity is adjusted to control the light transmitted through the liquid crystal layer, thereby obtaining a desired image. The polarity of a data voltage with respect to the common voltage is inverted for every frame, every column, or every pixel, when it is desired to prevent deterioration that may result from a prolonged application of the electrical field to the liquid crystal layer.
Typically, a display device such as a liquid crystal display or an organic light emitting display device, include a display panel constituted of pixels having switching elements and display signal lines; a gate driver configured to supply gate signals to gate lines that operate (turn on/off) the pixel switching elements; a gray-scale level voltage generator configured to generate a plurality of gray-scale level voltages; a data driver configured to select a data voltage corresponding to image data among the gray-scale level voltages, and to apply the data voltage to the data lines of the display signal lines; and a signal controller configured to control the gate driver, the data driver, and the gray-scale level voltage generator.
In general, am image characteristic of the above-described liquid crystal display device, such as image quality or brightness of a screen, may vary in accordance with a gamma curve, in which the relationship between a gray-scale level and brightness is determined. When a default value that is initially set to provide a desired brightness value (hereinafter, referred to as ‘target brightness value’), it generally is not necessary to set the default value again. However, in many cases, it is difficult to maintain the desired target brightness value. Therefore, a gray-scale value corresponding to the desired target brightness value may need to be set again. However, if it takes a long time to set the target brightness value, the productivity of the display user can be reduced. Thus, it is desirable to adjust gray-scale level values in a display device quickly.